Why objects should be top of mind for m-commerce site developers

Three of the 30 merchants on the Keynote Mobile Commerce Performance Index completed m-commerce site performance tests last week with zero object errors. All three landed in the top four rankings of the index. Learn what an object error is and why mobile retailers should beware.

When retailers are crafting their mobile commerce sites and considering page load speed there are two important factors to consider. One is the load time of the base page—the HTML file, the bones of the site. After that loads, the site begins to load all the page objects or content outlined in that HTML file, including images and buttons, text, JavaScript (which controls how elements behave, such as making images scroll), and tags (which, for example, could track mobile analytics).

How a page is constructed and the order in which content is loaded play a big role in how quickly a page will be displayed, says Herman Ng, mobile performance evangelist at mobile and web performance monitoring, testing and analytics firm Keynote. Downloading certain types of content first can optimize load time, while other types of content, such as many JavaScript files that are slow to load, can block everything behind them from loading until they load completely, he says.

“Just one problematic object that continuously times out during page load could cause the overall page load time to increase dramatically, even when the page is well optimized for mobile devices,” Ng says. “If any of the problematic objects are a crucial part of the page, such as the CSS and JavaScript objects, it might actually delay or prevent the rendering of the entire page.”

Another mistake mobile retailers sometimes make is choosing to load objects first that are not crucial to shopping. Below-the-fold content not immediately seen on the mobile screen and third-party tags are examples of content that can wait, Ng says. For example, an ad network’s tracking tag may need to connect to a remote server, but the consumer doesn’t need it to load before she can view the page. Therefore, a retailer should make it one of the last objects on a page to load so that it does not block essential page content.

Three out of the 30 retailers on the index loaded all home page objects without errors over the entire week. All three landed in the top four rankings on the index—Toolfetch.com LLC (No. 1), W.W. Grainger Inc. (No. 2) and Walgreen Co. (No. 4).

J.C. Penny, which ranked third on the index, had only three object errors. Minimizing object errors improves mobile site performance, Ng says. Of the other retailers on the index, 14 registered object errors on fewer than 10% of home page objects, eight on between 10% to 100% of home page objects, and four registered more object errors than successful page loads, meaning they consistently had more than one object error each time their mobile page was loaded.

Toolfetch.com topped the Keynote Mobile Commerce Performance Index for the week ending March 2. Its average load time was 2.31 seconds and its success rate was 99.83% for a score of 961. Keynote weights and combines load time and success rate to reach a score. Toolfetch.com’s mobile home page contains six elements weighing 65 kilobytes. Grainger came in second with an average load time of 2.77 seconds and a success rate of 99.65% for a score of 958. Its mobile home page contains eight elements weighing 82 kilobytes.

Two of the 30 retailers on the index offer responsive design sites, which use a single code base, a single set of web content and responsive techniques to render versions of the site that fit the size of the screen on a device a consumer is using. This saves a retailer having to build separate sites for desktops, tablets, smartphones and other devices, and delivers content from a single URL, which tends to strengthen search engine rankings.

Fab.com, one of the responsive sites, came in at No. 23 with a load time of 14.72 seconds and a success rate of 99.65% for a score of 565. Fathead.com LLC, the other responsive site, came in at No. 28 with a load time of 15.96 seconds and a success rate of 99.27% for a score of 458. The No. 1 complaint about responsive design sites is that they load slower than standalone sites because responsive sites transmit more data to mobile web browsers than standalone sites. However, responsive design is quickly evolving in ways that improve performance.

The average load time for all 30 retailers on the index was 7.79 seconds, the average success rate was 99.40% and the average score was 759.

Click here then click on Keynote Mobile Commerce Performance Index Part 1 and Part 2 to view complete results for all 30 retailers on the index. Keynote measures, exclusively for Internet Retailer, 28 standalone m-commerce sites optimized for smartphones and two responsive design sites, which are single sites that render content in ways that fit the screen size of a device, including desktop PCs, tablets, smartphones and smart TVs. For the index, Keynote measures the smartphone versions of the responsive sites.

The 30 representative sites include merchants in multiple categories and channels, and of multiple sizes, ranging from such giants as Amazon.com Inc. to mid-sized retailers like Toolfetch.com LLC. Keynote tests the sites in the index every hour Monday through Sunday from 8:00 a.m. through midnight EDT, emulating two different smartphones on two different wireless networks: Apple Inc.’s iPhone 5 on AT&T and the Samsung Galaxy SIII on T-Mobile, both using 4G networks. Keynote runs the tests in New York and San Francisco.

Keynote combines a site’s load time and success rate, equally weighted, into a single score. Given that both performance and availability are important, the score reflects the overall quality of the home page; a higher score indicates better performance. Scores also reflect how close sites are to each other in overall quality. The index average score is the midpoint among all the sites’ scores. To consistently rank high on the Keynote index, sites must hit availability targets of 99.5% or better and be faster than 10 seconds to load on average. Top-performing sites load in under five seconds.

While adoption among U.S. consumers has been steadily rising, only a fraction of all U.S. wireless connections are 4G. Consequently, retailers benchmarking their mobile commerce site performance against the Keynote index should keep in mind that most of their m-commerce site shoppers will experience page load times slower than those on the index.